Ultra-High-Frequency Reprogramming of Individual Long-Term Hematopoietic Stem Cells Yields Low Somatic Variant...

Area of Science:

• Stem cell biology
• Cellular reprogramming
• Hematopoiesis

Background:

• Reprogramming adult human cells into induced pluripotent stem cells (iPSCs) is crucial for regenerative medicine but has low efficiency.
• Identifying cell types amenable to efficient reprogramming is essential for clinical applications.

Purpose of the Study:

• To investigate the reprogramming efficiency of adult human long-term hematopoietic stem cells (LT-HSCs).
• To compare the genetic stability and mutation load of LT-HSCs versus skin fibroblasts for iPSC generation.

Main Methods:

• Senadi virus transduction of isolated CD49f+ LT-HSCs.
• Analysis of reprogramming efficiency across different hematopoietic progenitor stages.
• Whole-genome sequencing and mutation analysis of paired LT-HSC and fibroblast samples.

Main Results:

• Individual adult human LT-HSCs can be reprogrammed into iPSCs with nearly 50% efficiency.
• Reprogramming efficiency decreases significantly in more committed hematopoietic progenitors.
• LT-HSCs possess a lower load of somatic single-nucleotide variants (SNVs) and indels compared to skin fibroblasts.
• LT-HSCs and fibroblasts exhibit distinct somatic mutation signatures, with most mutations predating reprogramming.

Conclusions:

• LT-HSCs demonstrate exceptional susceptibility to reprogramming, surpassing other cell types.
• The lower mutation burden and distinct mutational profile of LT-HSCs make them a promising source for clinical-grade iPSC production.
• Optimizing reprogramming protocols, particularly cell cycle status, can further enhance efficiency.